Engine Rebuild Question...

Have a rebuilt 305 with a 2 barrel
in my 77 GMC. It came stock
with a 454 but someone had yanked
it for another project (still crying over
spilt milk).

My issue is that at low end I have
NO power. I know, I Know, It's a
305!!!! Well, I just feel theres
something that can be done to cure it.
It does have power once the RPMs
get up there a bit. Albeit 305 power.
This is all I'm looking for in the low
end. Is there any combination of
carb/cam/etc. that might allow me to
get this power down low without spending
an arm and a leg or doing a complete
rebuild (which If I do will be done on
a 350 block)?

might try some 1.6 ratio rocker arms instead of a cam swap. this will help a little, but if you don't have the deep gears and convertor to go along, you will only be making higher rpms available. what is your compression ratio? might want to try some 350 heads. a 041,487,044,461,186 or 993 head might work better for you to get some low end.good luck and give some feedback on what you do. bye,Neil

Check first on your gearing. Maybe they are 3.07s and that's why you don't feel any low end torque. You may want to go with 3.73 or even 4.11, depending on tire size, which by the way, size tires are you running?

If you are thinking of a head swap, the L31 Vortec heads are the only way to go. You can mail order them from PaceParts.com for just a little over $400. They outflow all previous castings, and with the new combustion chamber configuration they improve flame travel and increase efficeincy. Dollar for dollar they are one of the best engine mods that you can make. Just my opinion. By the way, you will need new self-aligning rockers($50) and a new Vortec style intake($150).

I believe the tires are 245/75/16. Shouldn't be the problem. Gearing I am not sure of but it came with a 454. Wouldn't such a model be geared low to start? What are costs for re-gearing to say a 3.73 or lower if it is in fact a 3.07? I know, lotsa questions and very few answers... :-))

Neil, Honestly I know very little about what's in there. I see some posts regarding head changes... If I go to that extent I think I'll just do a 350. I've never rebuilt one and I think it would be a good learning experience.

Useful Searches

>
About Us>
>
In May of 1999 CK5 started out as a tribute to America's favorite 4x4 utility truck. Since then it has grown to be
a leader among full size Chevrolet K5 Blazer and GMC Jimmy web sites across the Internet. CK5 has since expanded
to include the C/K series GM Truck and Suburban as well as past and present GM models.
>>
With its technical articles, factory specifications, photo gallery, classifieds, active message forum, product
reviews and original automotive content it's an unbeatable source.